code: plan9front

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Mail: separate deletion from relinking messages

Mutating lists that are being iterated is needlessly error
prone, and we were removing the wrong message in some cases
if it the dummy got inserted in the right place.

Separating deletion into a redraw/relink and zap phase
simplifies the problem.

--- a/sys/src/cmd/upas/Mail/mail.h

+++ b/sys/src/cmd/upas/Mail/mail.h

@@ -15,6 +15,7 @@

 	Sdummy	= 1<<0,	/* message placeholder */

 	Stoplev	= 1<<1,	/* not a response to anything */

 	Sopen	= 1<<2,	/* opened for viewing */

+	Szap	= 1<<3, /* flushed, to be removed from list */

 };

 enum {

--- a/sys/src/cmd/upas/Mail/mbox.c

+++ b/sys/src/cmd/upas/Mail/mbox.c

@@ -144,7 +144,7 @@

 				break;

 			o += p->child[i]->nsub + 1;

 		}

-		if(!(p->state & Sdummy)){

+		if(!(p->state & (Sdummy|Szap))){

 			o++;

 			d++;

 		}

@@ -157,7 +157,7 @@

 			break;

 		if(m->state & Stoplev){

 			n += mbox.mesg[i]->nsub;

-			if(!(m->state & Sdummy))

+			if(!(m->state & (Sdummy|Szap)))

 				n++;

 		}

@@ -679,18 +679,17 @@

 	char *path;

 	Mesg *m, *p;

-	i = 0;

 	path = estrjoin(maildir, "/ctl", nil);

 	fd = open(path, OWRITE);

 	free(path);

 	if(fd == -1)

 		sysfatal("open mbox: %r");

-	while(i < mbox.nmesg){

+	for(i = 0; i < mbox.nmesg; i++){

 		m = mbox.mesg[i];

-		if((m->state & Sopen) || !(m->flags & (Fdel|Ftodel))){

-			i++;

+		p = m->parent;

+		if(m->state & (Sopen|Szap) || (m->flags & (Fdel|Ftodel)) == 0)

 			continue;

-		}

+

 		ln = mesglineno(m, nil);

 		fprint(mbox.addr, "%d,%d", ln, ln+m->nsub);

 		write(mbox.data, "", 0);

@@ -697,20 +696,26 @@

 		if(m->flags & Ftodel)

 			fprint(fd, "delete %s %d", mailbox, atoi(m->name));

-		p = m->parent;

 		removeid(m);

+		m->state |= Szap;

 		if(p == nil && m->nsub != 0){

 			p = placeholder(m->messageid, m->time, 1);

 			p->nsub = m->nsub + 1;

-			mbox.mesg[i] = p;

 		}

 		if(p != nil)

 			relinkmsg(p, m);

 		for(j = 0; j < m->nchild; j++)

 			mbredraw(m->child[j], 1, 1);

-		memmove(&mbox.mesg[i], &mbox.mesg[i+1], (mbox.nmesg - i)*sizeof(Mesg*));

-		mbox.nmesg--;

  	}

+

+	for(i = 0, j = 0; i < mbox.nmesg; i++){

+		m = mbox.mesg[i];

+		if((m->state & Szap) != 0)

+			mesgfree(m);

+		else

+			mbox.mesg[j++] = m;

+	}

+		

 	close(fd);

 	fprint(mbox.ctl, "clean\n");

 }